Boring bar



July 31, E A. ZEMPEL 2,380,627

' BORING BAH Filed Feb.. l, 1943 INVENTOR EDWARDAZEMPEL ATToPNe'Ys Patented July 3 1, 1945 UNITED STAT-ES e' PATENT OFFICE `,2,380,627 Y BORING BAR Edward A. Zempel, Milwaukee, Wis. Application February 1, 1943,*Serla-l No. 474,301

(ci. ir-s) 1 Claim.

This invention appertains to boring bars and more particularly to boring bars having single or double adjustable cutters.

One of the primary objects of my invention is to provide a boring bar having a novel micrometer adjustment for advancing and retracting the cutters, whereby the cutters can be accurately moved to the correct and desired diameter.

Another salient object of my invention is to provide a double cutter boring bar with means including a rotatable calibrated micrometer dial for simultaneously adjusting the cutters to the proper position without the use of any extraneous precision instruments.

A further object of my invention is `to provide a single adjustable member for locking both of the cutters after adjustment, so that the cutters will be positively held to the desired diameter during the boring operation.

A further important object of my invention is to provide a micrometer adjustable boring bar in which the cutters can be quickly removed and replaced in the bar Without the necessity of removing any other parts of the bar, the cutters being of identical construction whereby interchangeability can be had.

A still further object of my invention is to provide an adjustable boring bar of the above character. which will be durable and efficient in use, one,` that embodies a minimum number of working parts and one which can be manufactured and placed upon the market at a reasonable cost.

With these and other objects in view the invention consists in the novel construction, ar rangement and formation of parts, which will be hereinafter more specifically described, claimed, and illustrated in the accompanying drawing, in which drawing:

Figure l is a fragmentary, longitudinal, sectional view through a slightly modified form of my invention.

Figure 2 is a transverse, sectional view through the bar taken on the line 2-2 of Figure 1 looking in the direction of the arrows.

Figure 3 is a similar view taken on the line 3-3 of Figure 1; and f Eigure 4 is a transverse, sectional view through the bar taken on the line 4-4 of Figure 1 looking in the direction of the arrows.

Referring to the drawing in detail, wherein similar reference characters designate corresponding parts, throughout the several views, the letter B generally indicates my novel micrometer adjustable boring bar and the same includes an elongated shank 30 reduced in diameter at its forward end to provide a stop shoulder 3|. The bar forwardly of the shoulder is provided with a diametrically extending longitudinal slct 32 and the forward end of the bar in rear of the pilot 33 is provided with a similar slot 34. The opposite sides of the bar are provided with longitudinally extending grooves 35 and these grooves open into the slots 32 and 34. The rear slot 32 slidably receives a guide plate 36 and the ends of this plate protrude slightly beyond this slot and are rounded and are provided with dine threads. An adjusting dial or sleeve 31 is rotatably mounted on the bar and is fitted against the shoulder 3i and is held on the bar by a cylindrical casing 3B which is fitted on the bar against the forward end of said sleeve. The forward end of the cylindrical casing is provided with a head 39 and the forward end of the head 39 has its opposite sides provided with notches 40 which register with the opposite ends of the forward slot 34. If desired, the head 39 can be made separate from the cylindrical casing 38 and the head 39 is held on the bar by a suitable pin or set screw.

The forward slot 34 slidably receives the adjusting plate or plunger 4l and the forward end of the plate or plunger is operatively connected to the cutters 42 and 43 by mating ribs and grooves. The guide plate 36 is connected to the adjusting plate 4I by rods 44 and these rods are adapted to seat within the longitudinal grooves 35 formed in the bar. The rear ends of the rods 44 are threaded into the guide plate 36 and the forward ends of the rods are provided with inwardly directed feet 45 which are adapted to snap into sockets 46 formed on the opposite sides of the adjusting plate 4 I.

Obviously by turning the micrometer dial or sleeve 31, the guide plate 36 can be advanced or retracted and this movement will be transferred to the plunger or adjusting plate 4I.

In assembling this type of cutter, the guide plate 36 is rst placed into the slot 32 and the rods 44 are laid in the grooves 35 and are threaded into the guide plate by turning these rods. During the turning of the rods the forward ends of the rods can be sprung outwardly to facilitate rotation thereof. The micrometer or dial 31 can then be placed in position after which the plunger or adjusting plate 4| is placed in the slot and the forward ends of the rods 44 are sprung out and then snapped into the sockets 46. The cylindrical casing 38 can then be placed on the bar and held in position. The bar is now ready for the reception of the cutters. It is to be understood that the forward end of the adjusting sleeve 31 is graduated and these graduations cooperate with the zero mark on the end of the casing.

From the foregoing description it can be seen that I have provided an exceptionally simple and durable form of double cutter boring bar which embodies a minimum number of operating parts.

Changes in details may be made without departing from the spirit or the scope of my in vention, but what I claim as new is.:

An extension boring bar comprising an elongated body having its forward end reduced in diameter deining an annular stop shoulder, said body being provided with a diametrically extending slot forwardly of the shoulder and a similar slot forwardly of the rst slot and adjacent but spaced from the forward end of the body, a guide plate tted in the first slot for sliding movement, an adjusting plate fitted in the second slot for sliding movement, means connecting said plates together, a rotatable adjusting sleeve mounted on the body against the shoulder for yadvancing and retracting the guide plate, a casing ntted on. the body against the sleeve, a head on the forward end of the casing provided with notches registering with the second slot, cutters insertable in the opposite ends of the slot through said notches, the inner ends of the cutters and the forward end of the adjusting plate having inter-engaging inolined ribs and grooves said means for connecting the plates together including spaced longitudinally extending rods disposed on opposite sides of the body, and said body having longitudinal guide grooves communicating with the slots slidably receiving the rods.

EDWARD A. ZEMPEL. 

